docs: def save(self, commit=True, **kwargs):
          '''
          PeriodicTask is dynamic and save behavior changed
          See: https://github.com/zakird/celerybeat-mongo/commit/dfbbd20edde91134b57f5406d0ce4eac59d6899b
          '''
          if not self.instance:
              self.instance = self.model_class()  # Force populate_obj in super()
          return super(PeriodicTaskForm, self).save(commit, **kwargs)